Interesting scenario. Lots of ways to look at this and things to consider, many set out above.
I looked at it this way. Say that you can live on 53K per year and that you can save above that, i.e. save the 148k lump sum or save the 12k (net 5,400 per your numbers, ie 12k less 6,600).
How long would it take saving the 5,400 per year to save 148k? Need to obviously factor in annual interest, return? What should this be. I assumed 2% net in my first calculation. I also assume that you both continue to live.
By my calculation you would need to live to 98 at which time the money saved by saving the 5,400 each year at 2% interest would be the same as the amount if you saved 148,000 on day one also at a 2% return. (pretty much 148,000 divided by 5,400 = 27.4 years, with increase due to interest on larger cash lump sum up front)
Very simplistic, but sometimes simplicity helps to focus the mind.
Also if you were to pass away before 98 then your wife gets 2,700 per year (??) so she would need to live most likely way beyond 100 for the sums to add up.
(At an annual return of 1%, the two amounts would correspond at your age of 91. 3% annual return net, age 114!!).
All other things being equal I would think the cash makes more sense.
However, health care, nursing homes, etc. Risk that any cash lump sums will be factored into the cost of nursing homes so can't discount those. I can't get away from the security of knowing that there is a significant cash lump sum available and under your direct control, should something happen.
Forget to say, obviously seek a better computation ratio.